Cataclysm Caster Agility versus Critical Strike

There have been quite a few arguments lately on whether Agility will grant any crits onto spell casts. The tooltip on our paperdoll says "Increases Critical Hit chance by 4.10%".
Which is confusing in itself.. does it means whether the spell being cast has a 4.10% chance native or added chance to proc a critical cast? The word "hit" implies a target... oh well. Let's test it!

Using my level 40 human holy specced paladin as the guinea pig, attacking a Stormwind training dummy, and the addon Recount to capture the results, here are my results:

Stats before testing:

• Buffs: none.
• Gear: none.
• Strength: 70
• Agility: 46
• Intellect: 49
• Spirit: 53
• Total Mana: 1442
• Spell Power: 39
• Spell Crit Chance: 5.37%
• Mana Regen: 64
• Combat Regen: 57
• Holy Light cost: 88 mana
• Holy Light cast time: 2.5 seconds

Test Runs: attacking a training dummy + drinking moonberry juice:

1. 200 Holy Lights cast, we had 10 crits (5.0%).

This is right near the 5.7% crit chance shown on the paperdoll ( error expected with such a small sample size ).

Okay, let's put on some pure +agility gear. And run the same test again!

Stats after gear changes:

• Buffs: none.
• Gear: pure +agility.
• Strength: 70
• Agility: 107
• Intellect: 49
• Spirit: 53
• Total Mana: 1442
• Spell Power: 39
• Spell Crit Chance: 5.37%
• Mana Regen: 64
• Combat Regen: 57
• Holy Light cost: 88 mana
• Holy Light cast time: 2.5 seconds

Test Runs: attacking a training dummy + drinking moonberry juice:

1. 200 Holy Lights cast, with 7 crits (3.5%).

Conclusion: stacking Agility in World of Warcrft: Cataclysm does NOT increase your spell criticals ( at least healing :P ).